A new electric bike approved for use on high-speed roads has been showcased at the EV World exhibition in Dubai. But its top-speed of 110kph has led to renewed concerns over the safety and regulation of high-performance electric two-wheelers.The Zero XE recently went on sale in Abu Dhabi for Dh25,000 ($6,800). It comes fitted with lights, indicators, a horn and a number plate. Zero Motorcycles, its US manufacturer, said the bike has been…